/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: SAX2DOM.java,v 1.8.2.1 2006/12/04 18:45:41 spericas Exp $
 */


package com.sun.org.apache.xalan.internal.xsltc.trax;

import java.util.Stack;
import java.util.Vector;
import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import com.sun.org.apache.xalan.internal.xsltc.runtime.Constants;

import org.w3c.dom.Comment;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.Text;
import org.w3c.dom.ProcessingInstruction;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.ext.Locator2;

/**
 * @author G. Todd Miller
 * @author Sunitha Reddy
 * @author Huizhe Wang
 */
public class SAX2DOM implements ContentHandler, LexicalHandler, Constants {

  private Node _root = null;
  private Document _document = null;
  private Node _nextSibling = null;
  private Stack _nodeStk = new Stack();
  private Vector _namespaceDecls = null;
  private Node _lastSibling = null;
  private Locator locator = null;
  private boolean needToSetDocumentInfo = true;

  //Replace StringBuffer with StringBuilder now that we no long support jdk1.4
  private StringBuilder _textBuffer = new StringBuilder();
  private Node _nextSiblingCache = null;
  /**
   * JAXP document builder factory. Create a single instance and use
   * synchronization because the Javadoc is not explicit about
   * thread safety.
   */
  private DocumentBuilderFactory _factory =
      DocumentBuilderFactory.newInstance();
  private boolean _internal = true;

  public SAX2DOM(boolean useServicesMechanism) throws ParserConfigurationException {
    _document = createDocument(useServicesMechanism);
    _root = _document;
  }

  public SAX2DOM(Node root, Node nextSibling, boolean useServicesMechanism)
      throws ParserConfigurationException {
    _root = root;
    if (root instanceof Document) {
      _document = (Document) root;
    } else if (root != null) {
      _document = root.getOwnerDocument();
    } else {
      _document = createDocument(useServicesMechanism);
      _root = _document;
    }

    _nextSibling = nextSibling;
  }

  public SAX2DOM(Node root, boolean useServicesMechanism) throws ParserConfigurationException {
    this(root, null, useServicesMechanism);
  }

  public Node getDOM() {
    return _root;
  }

  public void characters(char[] ch, int start, int length) {
    // Ignore text nodes of length 0
    if (length == 0) {
      return;
    }

    final Node last = (Node) _nodeStk.peek();

    // No text nodes can be children of root (DOM006 exception)
    if (last != _document) {
      _nextSiblingCache = _nextSibling;
      _textBuffer.append(ch, start, length);
    }
  }

  private void appendTextNode() {
    if (_textBuffer.length() > 0) {
      final Node last = (Node) _nodeStk.peek();
      if (last == _root && _nextSiblingCache != null) {
        _lastSibling = last
            .insertBefore(_document.createTextNode(_textBuffer.toString()), _nextSiblingCache);
      } else {
        _lastSibling = last.appendChild(_document.createTextNode(_textBuffer.toString()));
      }
      _textBuffer.setLength(0);
    }
  }

  public void startDocument() {
    _nodeStk.push(_root);
  }

  public void endDocument() {
    _nodeStk.pop();
  }

  private void setDocumentInfo() {
    //try to set document version
    if (locator == null) {
      return;
    }
    try {
      _document.setXmlVersion(((Locator2) locator).getXMLVersion());
    } catch (ClassCastException e) {
    }

  }

  public void startElement(String namespace, String localName, String qName,
      Attributes attrs) {
    appendTextNode();
    if (needToSetDocumentInfo) {
      setDocumentInfo();
      needToSetDocumentInfo = false;
    }

    final Element tmp = (Element) _document.createElementNS(namespace, qName);

    // Add namespace declarations first
    if (_namespaceDecls != null) {
      final int nDecls = _namespaceDecls.size();
      for (int i = 0; i < nDecls; i++) {
        final String prefix = (String) _namespaceDecls.elementAt(i++);

        if (prefix == null || prefix.equals(EMPTYSTRING)) {
          tmp.setAttributeNS(XMLNS_URI, XMLNS_PREFIX,
              (String) _namespaceDecls.elementAt(i));
        } else {
          tmp.setAttributeNS(XMLNS_URI, XMLNS_STRING + prefix,
              (String) _namespaceDecls.elementAt(i));
        }
      }
      _namespaceDecls.clear();
    }

    // Add attributes to element
/*      final int nattrs = attrs.getLength();
        for (int i = 0; i < nattrs; i++) {
            if (attrs.getLocalName(i) == null) {
                tmp.setAttribute(attrs.getQName(i), attrs.getValue(i));
            }
            else {
                tmp.setAttributeNS(attrs.getURI(i), attrs.getQName(i),
                    attrs.getValue(i));
            }
        } */

    // Add attributes to element
    final int nattrs = attrs.getLength();
    for (int i = 0; i < nattrs; i++) {
      // checking if Namespace processing is being done
      String attQName = attrs.getQName(i);
      String attURI = attrs.getURI(i);
      if (attrs.getLocalName(i).equals("")) {
        tmp.setAttribute(attQName, attrs.getValue(i));
        if (attrs.getType(i).equals("ID")) {
          tmp.setIdAttribute(attQName, true);
        }
      } else {
        tmp.setAttributeNS(attURI, attQName, attrs.getValue(i));
        if (attrs.getType(i).equals("ID")) {
          tmp.setIdAttributeNS(attURI, attrs.getLocalName(i), true);
        }
      }
    }

    // Append this new node onto current stack node
    Node last = (Node) _nodeStk.peek();

    // If the SAX2DOM is created with a non-null next sibling node,
    // insert the result nodes before the next sibling under the root.
    if (last == _root && _nextSibling != null) {
      last.insertBefore(tmp, _nextSibling);
    } else {
      last.appendChild(tmp);
    }

    // Push this node onto stack
    _nodeStk.push(tmp);
    _lastSibling = null;
  }

  public void endElement(String namespace, String localName, String qName) {
    appendTextNode();
    _nodeStk.pop();
    _lastSibling = null;
  }

  public void startPrefixMapping(String prefix, String uri) {
    if (_namespaceDecls == null) {
      _namespaceDecls = new Vector(2);
    }
    _namespaceDecls.addElement(prefix);
    _namespaceDecls.addElement(uri);
  }

  public void endPrefixMapping(String prefix) {
    // do nothing
  }

  /**
   * This class is only used internally so this method should never
   * be called.
   */
  public void ignorableWhitespace(char[] ch, int start, int length) {
  }

  /**
   * adds processing instruction node to DOM.
   */
  public void processingInstruction(String target, String data) {
    appendTextNode();
    final Node last = (Node) _nodeStk.peek();
    ProcessingInstruction pi = _document.createProcessingInstruction(
        target, data);
    if (pi != null) {
      if (last == _root && _nextSibling != null) {
        last.insertBefore(pi, _nextSibling);
      } else {
        last.appendChild(pi);
      }

      _lastSibling = pi;
    }
  }

  /**
   * This class is only used internally so this method should never
   * be called.
   */
  public void setDocumentLocator(Locator locator) {
    this.locator = locator;
  }

  /**
   * This class is only used internally so this method should never
   * be called.
   */
  public void skippedEntity(String name) {
  }


  /**
   * Lexical Handler method to create comment node in DOM tree.
   */
  public void comment(char[] ch, int start, int length) {
    appendTextNode();
    final Node last = (Node) _nodeStk.peek();
    Comment comment = _document.createComment(new String(ch, start, length));
    if (comment != null) {
      if (last == _root && _nextSibling != null) {
        last.insertBefore(comment, _nextSibling);
      } else {
        last.appendChild(comment);
      }

      _lastSibling = comment;
    }
  }

  // Lexical Handler methods- not implemented
  public void startCDATA() {
  }

  public void endCDATA() {
  }

  public void startEntity(java.lang.String name) {
  }

  public void endDTD() {
  }

  public void endEntity(String name) {
  }

  public void startDTD(String name, String publicId, String systemId)
      throws SAXException {
  }

  private Document createDocument(boolean useServicesMechanism)
      throws ParserConfigurationException {
    if (_factory == null) {
      if (useServicesMechanism) {
        _factory = DocumentBuilderFactory.newInstance();
        if (!(_factory instanceof com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl)) {
          _internal = false;
        }
      } else {
        _factory = DocumentBuilderFactory.newInstance(
            "com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl",
            SAX2DOM.class.getClassLoader()
        );
      }
    }
    Document doc;
    if (_internal) {
      //default implementation is thread safe
      doc = _factory.newDocumentBuilder().newDocument();
    } else {
      synchronized (SAX2DOM.class) {
        doc = _factory.newDocumentBuilder().newDocument();
      }
    }
    return doc;
  }

}
